JP3145957B2 - Waste treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a waste treatment method for subjecting a biodegradable solid organic waste to methane fermentation.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No. Hei.
There are known sewage treatment methods described in Japanese Patent No. 54692 and Japanese Patent Application Laid-Open No. 3-165895.

In the sewage treatment method described in Japanese Patent Application Laid-Open No. 3-154693, when organic sewage is subjected to methane fermentation treatment with the above-mentioned methane-producing bacteria, the TOC (Total Orifice) is used.
ganic Carbon) When the load is increased from 4 kg / m ³ · day to 5 kg / m ³ · day, overload occurs and the TOC removal rate drops rapidly, resulting in overload and treatment efficiency. When the concentration decreases, nickel, cobalt, nitrogen, and phosphorus necessary for metabolism of methanogens are appropriately added to recover the treatment efficiency.

Further, in the sewage treatment method described in Japanese Patent Application Laid-Open No. 3-165895, BOD (Biochemical Oxyg
en Demand: Biochemical oxygen demand) Load is 3 kg / m ³
-Since the BOD removal rate decreases when the temperature is higher than the day, nickel, iron, and cobalt, which are nutrients of methane-producing bacteria, are appropriately added so that the BOD concentration of the organic waste becomes a predetermined amount or more, and methane generation is performed. Improve the growth activity of bacteria,
Even if the BOD load increases, a decrease in the BOD removal rate is prevented.

[0005]

However, the above-mentioned Japanese Patent Application Laid-Open Nos. Hei 3-154692 and Hei 3-1658 are disclosed.
In the sewage treatment method described in Japanese Patent Publication No. 95, the treatment is performed by increasing the TOC load and the BOD load in order to improve the treatment efficiency. However, the amount of methane gas generated when performing methane fermentation treatment with methane-producing bacteria is as follows. not many. And TOC
When the load and the BOD load are further increased to increase the amount of methane gas generated, the thermal energy for heating the methane fermentation digester for methane fermentation also increases in proportion. For this reason, even if the TOC load or the BOD load is increased, it is not possible to recover energy by effectively using the obtained methane gas as another energy source.

Therefore, as a method of increasing the amount of methane gas generated, for example, a solid solution that can be decomposed by anaerobic microorganisms such as garbage and kitchen garbage collected from homes and business establishments where urgent treatment measures are desired. Crushing waste containing organic waste in a form to improve biodegradability, mixing water and mixing organic wastewater to prepare crushed material, and subjecting this crushed material to methane fermentation treatment Can be considered. It is known that the waste containing the solid organic waste contains nickel, iron, and cobalt, which are nutrients for methanogens.

[0007] However, when the concentration of the crushed material is increased in order to increase the amount of methane gas generated and recover energy, the TOC load, COD load, and BOD load become equal or lower. Even under the conditions described above, the accumulation of organic acids may occur, and the methane fermentation treatment may be reduced or stopped.

The present invention has been made in view of the above problems, and provides a waste treatment method capable of efficiently and simply treating waste containing solid organic waste and effectively utilizing the generated methane gas. With the goal.

[0009]

According to a first aspect of the present invention, there is provided a waste treatment method comprising subjecting crushed material obtained by crushing waste containing solid organic waste decomposable by anaerobic organisms to methane fermentation treatment. In the waste treatment method, when the total evaporation residue in the crushed material during the methane fermentation treatment is 5% or more, at least one of an iron compound, a cobalt compound, and a nickel compound is added.

[0010] When the crushed material obtained by crushing the waste containing the solid organic waste is subjected to methane fermentation with an anaerobic organism, the total evaporation residue in the crushed material is 5%. In the case described above, the crushed material obtained by treating at a high concentration of the total evaporation residue in order to increase the amount of methane gas generated by adding at least one of the iron compound, the cobalt compound and the nickel compound. The nutrients of the anaerobic microorganisms contained therein are replenished with the increased inactive effect of iron, cobalt and nickel, thereby ensuring the balance of nutrients and improving the treatment efficiency of methane fermentation.

The waste treatment method according to claim 2 is a waste treatment method for subjecting organic wastewater decomposable by anaerobic microorganisms to methane fermentation, wherein the solid waste decomposable to the organic wastewater by anaerobic organisms. A waste containing organic waste in a form is crushed, stirred and mixed to prepare a mixture, and when the mixture is subjected to methane fermentation treatment, when the total evaporation residue of the mixture is 5% or more, iron compounds, cobalt At least one of a compound and a nickel compound is added.

When the organic wastewater is subjected to methane fermentation treatment with an anaerobic organism, the waste containing the solid organic waste is crushed and mixed to prepare a mixture, and the mixture is entirely evaporated. When the content is 5% or more, at least one of an iron compound, a cobalt compound, and a nickel compound is added to increase the amount of methane gas generated. The anaerobic microorganism nutrients contained in the crushed material are replenished with an increase in the inactive effect of iron, cobalt and nickel, thereby ensuring a nutrient balance and improving the treatment efficiency of methane fermentation.

According to a third aspect of the present invention, there is provided the waste disposal method according to the first or second aspect, wherein the waste is subjected to methane fermentation together with the solid matter of the human wastewater from which the waste is solid-liquid separated.

Then, in order to mix the solid matter of the human wastewater separated into solid and liquid during the methane fermentation treatment of the waste,
Nitrogen and phosphorus are replenished from the solid content of human wastewater, the activity of anaerobic microorganisms is improved, and the efficiency of methane fermentation is improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a waste disposal method according to the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes a pretreatment means, which is a waste containing mainly solid organic waste such as business waste such as garbage, kitchen garbage, and agricultural and marine waste. A crushing device (not shown) that breaks and crushes the material to remove synthetic resin bags, plastics, and the like, and removes metals by magnetic sorting while washing the crushed material with the crushing device. And a metal removing means (not shown).

The pre-processing means 1 is connected to an adjusting means 2. The adjusting means 2 includes nutrient chlorine added by adding at least one of an iron compound such as ferrous chloride, a nickel compound such as nickel chloride, and a cobalt compound such as cobalt chloride to the crushed organic waste. Means 3 is connected. Then, the adjusting means 2 appropriately adds at least one of an iron compound, a nickel compound, and a cobalt compound and water to the crushed organic waste, and heats the mixture to, for example, about 55 ° C. to 60 ° C. and stirs. A refined product is prepared as a slurry in which lumps are mixed with each other, that is, a crushed material in which lumps and liquids are mixed. Note that steam is preferably used for adding water and heating. By using steam, there is no need to add water and separately heat with heating means, and heating and stirring and mixing can be performed efficiently.

Further, the adjusting means 2 is connected to a methane fermentation digester 4 which constitutes a methane fermenting means for methane fermenting the refined material. This methane fermentation digestion tank 4 is a biological suspension type that can process even a thick slurry-like refined material containing solid or bulky organic waste and the like, and is heated, for example, appropriately stirred at 55 ° C to 60 ° C. Then, organic substances in the organic waste are subjected to methane fermentation treatment with anaerobic microorganisms such as methanogens.

The methane fermentation digester 4 is provided with methane gas collecting means (not shown) for collecting generated methane gas, and the methane gas collecting means is connected to a gas tank 5 for storing the collected methane gas. A part of the collected methane gas is used for power generation and the like, and is used as operating energy when treating organic waste.

In the methane fermentation digester 4, the fermented product obtained by the methane fermentation treatment is subjected to filtration separation using a screen or membrane, sedimentation separation treatment, centrifugal separation treatment, etc. Is connected to a solid-liquid separation means 6 for performing solid-liquid separation. Further, a return means having a return pipe 7 for returning the separated liquid subjected to the solid-liquid separation to the adjusting means 2 is connected to the solid-liquid separation means 6. In addition, the dewatered cake separated into solid and liquid is used for solid fuel, fertilizer, building materials, and the like.

Next, the operation of the above embodiment will be described.

First, waste containing solid organic waste that can be biodegraded by anaerobic microorganisms such as garbage and agricultural and marine wastes is put into the crushing and shredding device of the pretreatment means 1 and crushed. Bags and crushed synthetic resin bags and synthetic resin films,
Removes contaminants that cannot be decomposed by microorganisms such as plastic and glass. Then, the metal which is a foreign substance is removed by magnetic separation or the like while washing the crushed crushed material with a metal removing device.

Thereafter, the crushed material after the magnetic separation is introduced into the adjusting means 2. Then, in the adjusting means 2, the mixture is stirred and mixed while being heated to about 55 ° C. using, for example, steam.
Evaporation residue that can be stirred and mixed (Total Solids: TS)
A slurry-like refining material is prepared in which a lump having a concentration of 20% or less is mixed. If the TS concentration is higher than 20%, the stirring and mixing during the methane fermentation treatment become insufficient and the methane fermentation treatment cannot be performed efficiently. Therefore, the TS concentration is set to 20% or less, preferably 18% or less. In addition, by forming the slurry in a state in which there is little or almost no lump, the methane fermentation treatment by the microorganism proceeds more efficiently.

Here, the TS concentration of the tempered material was measured, and TS
When the concentration is 5% or more, preferably 7.5% or more, the nutrients adding means 3 adds at least one of iron compounds, nickel compounds, and cobalt compounds as nutrients. These nutrients are contained in the refined product in an amount of 10 mg / liter or more, preferably 10 to 3%, as iron.
00 mg / L, 1 mg / L or more, preferably 1 to 30 mg / L as nickel and 1 mg / L or more, preferably 1 to 30 mg / L as cobalt are added.

When the TS concentration is lower than 5%, trace effects of iron, nickel and cobalt contained in the organic waste are reduced due to agglomeration, sedimentation, scale formation, etc., and anaerobic. Since a sufficient amount of nutrients necessary for the activity of the microorganism can be obtained, it is not necessary to separately add nutrients.

On the other hand, if the amount of iron added is less than 10 mg / l, no improvement in the methane fermentation treatment in the subsequent stage is observed, and if it exceeds 300 mg / l, no difference in the effect due to the addition of iron is observed and the cost increases. Therefore, the amount of iron added is 10 mg / liter or more, preferably 10 to 300 mg.
Per liter of an iron compound. Similarly, when the amount of nickel added is less than 1 mg / liter, no improvement in the methane fermentation treatment in the subsequent stage is observed, and
Even if the amount is more than mg / liter, no difference in effect due to the addition of nickel is recognized and the cost increases. Therefore, the nickel compound is added so that the amount of nickel added is 1 mg / liter or more, preferably 1 to 30 mg / liter. Similarly, if the amount of cobalt added is less than 1 mg / liter, no improvement in the methane fermentation treatment in the subsequent stage is observed, and if it exceeds 30 mg / liter, no difference in the effect of the cobalt addition is observed and the cost increases. Therefore, the addition amount of cobalt is 1 mg / liter or more, preferably 1 to 3
A cobalt compound is added so as to be 0 mg / liter.

Then, the refined material to which nutrients are appropriately added is flown into the methane fermentation digestion tank 4 and, for example, is kept at 55 ° C. for 8 days while appropriately stirring, and the organic substance is methane-fermented by methane-producing bacteria or the like. To process. The methane gas generated by the methane fermentation treatment is collected by a methane gas collection means (not shown) and stored in a gas tank, which is used for the operation energy for the treatment of the organic waste such as power generation, other sewage treatment, and cooling and heating. Use.

Next, the fermentation product subjected to the methane fermentation treatment is solid-liquid separated into a dehydrated cake and separated water by solid-liquid separation means.
Then, the separated liquid is returned to the adjusting means 2 through the return pipe 7 of the returning means, and the dehydrated cake is used as a solid fuel, a building material, a fertilizer, or incinerated.

Here, iron, nickel and cobalt are substances that constitute a coenzyme component of microorganisms such as methanogens.
It is a nutrient element indispensable for improving the activity of microorganisms. In addition,
Iron is about 1000mg / l, nickel is about 80-24
0 mg / liter and about 50-150 mg of cobalt
When the amount is more than 1 g / liter, the activity of the microorganisms starts to be inhibited.

In the methane fermentation digester 4, unlike an organic wastewater, a high-concentration slurry-like mixture containing solid organic waste is treated.
Physicochemical reactions such as formation of scale fine particles and coprecipitation adsorption effect are occurring.

For this reason, when the TS concentration of the refined material fed into the methane fermentation digestion tank 4 which is the input TS concentration is lower than 5%, the concentration of the coagulation / sedimentation and scale forming substances in the methane fermentation digestion tank 4 is reduced. Relatively low, the inactive effect of iron, nickel, and cobalt, which are trace nutrients caused by physicochemical reactions such as coagulation / sedimentation and scale formation, is relatively low. It absorbs the active iron, nickel, and cobalt in it as a nutrient source, increases its activity, and efficiently decomposes organic substances. In the methane fermentation treatment method of a biological suspension type capable of treating solid organic waste, the BOD concentration is 30,000 to 50,000 pp.
m, the residence time is about 8 days, and the load (BO
D load: ³ to 5 kg / m ³ · day), that is, the upper limit processing condition under which anaerobic microorganisms can absorb active iron, nickel, and cobalt in the refined material as a nutrient source to decompose organic substances. .

On the other hand, when the TS concentration is 5% or more, especially 7.5%
As a result, the inactive effect of iron, nickel, and cobalt increases due to precipitation and scale formation, the activity decreases due to the lack of iron, nickel, and cobalt required by anaerobic microorganisms, and the above-mentioned processable TOC is reduced. Load, COD load, BO
The methane fermentation efficiency is greatly reduced or stopped even under the condition of the processing load at which the D load is equal or lower.

Therefore, as described above, in the above-described embodiment, methane fermentation digestion is performed when waste containing solid organic waste such as garbage, kitchen waste, and agricultural and marine waste is subjected to methane fermentation. 5% TS concentration when put into tank 4
When the above is satisfied, at least one of the iron compound, the nickel compound and the cobalt compound has an iron concentration of 10
３００300 mg / l, nickel concentration is 1-30 mg / l, and cobalt concentration is 1-30 mg / l.

For this reason, the TOC load, the COD load,
In the case where the nutrients are added when the BOD load is equal to or more than a predetermined value, even if the treatment load is set to a low value, for example, by increasing the residence time when treating a slurry-like mixture having a high concentration, In some cases, the methane fermentation treatment is reduced due to the imbalance in nutrients, so during treatment, the load is measured and the treatment efficiency is observed. It is necessary to appropriately add nickel, cobalt, etc., depending on the conditions, and the processing operation is complicated, and there is a problem that the apparatus becomes complicated and large. However, in the above-described embodiment, nutrients are added by adding nutrients corresponding to the concentration. Since the balance of salts is ensured, nutrients necessary for the activity of anaerobic microorganisms such as methanogens are supplemented, and methane fermentation treatment can proceed with high efficiency.

In addition, since plastics, glass, and other contaminants which cannot be treated by anaerobic microorganisms are removed in advance, it is possible to prevent agitation in methane fermentation and hindrance to liquid flow, and to achieve agitation with low load. In addition, the mixing of heavy metals such as cadmium and mercury can be reduced, almost uniform mixing is easy and efficient, and the increase of the inactive effect of nutrients due to impurities can be suppressed, improving the efficiency of methane fermentation. it can.

When methane fermentation is performed, COD
And simply measure the TS concentration, which is easier than BOD measurement,
During the methane fermentation treatment, it is only necessary to observe the treatment status to the degree of confirmation, and the TS concentration is a high-concentration slurry-like mixture containing solid organic waste that is difficult to measure by COD and BOD measurement methods. However, it can be easily measured, and methane fermentation can be easily performed.

In the above embodiment, the waste containing solid organic waste is prepared into a slurry-like refined product by steam and methane fermented. In addition, as shown in FIG. 2, for example, solid sludge such as debris and excess sludge generated during the treatment of human wastewater is mixed, and instead of water, drainage from agricultural and marine product processing plants is performed. It may be prepared by mixing organic sewage such as effluent from a beverage factory.

Organic wastes such as garbage, kitchen garbage, and agricultural and marine wastes are mainly composed of carbohydrates that are easily decomposed by methane fermentation. The nitrogen content is smaller than 20 which is the optimum ratio.
On the other hand, sludge separated from human wastewater has a high carbon / nitrogen ratio of 5 and a large amount of nitrogen and a large amount of phosphorus compounds. For this reason, by mixing the sludge with the organic waste, a good carbon / nitrogen ratio can be obtained, phosphorus as a nutrient source can be supplied, and the efficiency of the methane fermentation treatment in the subsequent stage can be further improved. Sludge generated during the treatment of sewage can also be treated, so that treatment efficiency can be improved, treatment facilities can be downsized, and treatment costs can be reduced. In addition, when organic wastewater is used, it can be treated together with organic waste, eliminating the need for a separate organic wastewater treatment step, improving treatment efficiency, miniaturizing treatment facilities, and reducing treatment costs. it can.

The mixture of solids and organic wastewater generated during the treatment of human wastewater is added to the methane fermentation digestion tank 4, for example, separately from the temper and mixed in the methane fermentation digestion tank 4. You may.

Also, the nutrients adding means 3 is provided in the adjusting means 2 and iron, nickel and cobalt are added in advance before the methane fermentation treatment, but iron, nickel and cobalt are added directly to the methane fermentation digester 4. Alternatively, it may be added from the adjusting means 2 to the methane fermentation digester 4 in the middle of a transport pipe for transporting the tempered product. The methane fermentation digester 4
However, in the case of a configuration in which stirring and mixing cannot be performed sufficiently, such as a configuration in which stirring is not always performed or a configuration in which stirring power is small, the adjusting means 2
It is preferable to mix them substantially uniformly by adding them in advance, or by adding them to a transport pipe for transporting the refined product from the adjusting means 2 to the methane fermentation digestion tank 4. In addition, the adjusting means 2 is generally heated to about the temperature at which it is treated in the methane fermentation digestion tank 4, promotes hydrolysis of organic waste and acid fermentation, and becomes a pH acidic condition to stabilize trace elements. Nutrients because it exists in a stable state, does not generate hydrogen sulfide, etc., prevents precipitation as sulfides and makes it unusable for microorganisms. Is preferred because of easy addition and simple structure.

Furthermore, in order to suppress the temperature change during the methane fermentation treatment in the subsequent stage, the preparation is described while heating with the adjusting means 2, but it is also possible to simply mix without heating. .

[0042]

First, vegetables, fruits, meat, fish, cooked rice and the like are mixed and pulverized to produce synthetic garbage having a water content of about 80% (TS concentration: about 20%). Then, water is appropriately added to prepare various refined products having different TS concentrations. Note that when the water is added and the dilution is approximately doubled, a TS having a TS concentration of about 10% is obtained, and when the dilution is 1.3 times with water, a TS having a TS concentration of about 15% is obtained. The TS concentration of these refined products and the residence time of the methane fermentation digester 4 were varied, and the state of methane fermentation treatment at 36 ° C., which is a medium temperature range in methane fermentation treatment, was observed. The results are shown in FIGS. The iron, cobalt, and nickel nutrients were reduced to about 200 mg / liter of ferrous chloride (88 mg / liter as iron) and about 40 mg / liter of cobalt chloride after 150 days from the start of operation when the methane fermentation treatment was reduced. (18 mg / liter as cobalt) was added continuously.

Here, FIG. 3A is a graph showing the situation where the TS concentration during the methane fermentation treatment is varied.
(B) is a graph showing the state of change in the chemical oxygen demand (COD _Cr ) due to the variable TS concentration and the variable residence time.

Here, the main composition of the garbage is C ₄₆ H
_Although it is known to be ₇₃ O ₃₁ N, the synthetic garbage has the following properties.

COD _Cr /TS=1.55 BOD / TS = 0.83 VS (Volatile Solid: volatile substance) /TS=0.90
8 TOC / TS = 0.45 Then, when processing is performed so that the residence time is variable, that is, the residence time is gradually shortened at the TS concentration shown in FIG.
As shown in FIG. 3A, the COD _Cr load increases. From the ratio of the above properties to TS, BOD
The load, VS load, and TOC load also increase.

When the synthetic garbage is subjected to methane fermentation under the conditions shown in FIGS. 3 (a) and 3 (b), the TS concentration becomes 7.5% and the methane gas generation amount becomes apparent as shown in FIG. 3 (c). At the same time, the acidity of the pH in the methane fermentation digestion tank 4 increases as shown in FIG. 3D, and as shown in FIG. 3E, volatile fatty acid (VFA) in terms of COD is obtained. Began to increase,
When the TS concentration becomes 10%, the methane gas generation amount shown in FIG. 3C, the pH shown in FIG.
The volatile fatty acid amount shown in (e) rapidly changed, and the methane fermentation treatment was stopped. Therefore, nutrients were added under the above conditions when 150 days had elapsed.

By the addition of the nutrients, the methane fermentation treatment is restored, and even if the TS concentration is increased to 15%, which is higher than 10%, or to 18%, which is the limit of stirring and mixing in the methane fermentation digestion tank 4, methane fermentation is sufficiently performed. It can be seen that fermentation can be performed.

Next, when the COD _Cr load is constant and the volume load is 9.5 g / liter / day (2.8 g / liter in terms of TOC load).
Example 1 in which the TS concentration of the above-mentioned synthetic garbage is varied so as to be 1 liter / day and nutrients are added under the above conditions.
Methane fermentation treatment in a medium temperature range of 36 ° C. FIG. 4 shows the results.

When the TS concentration becomes 5% or more, the acidity of the pH in the methane fermentation digestion tank 4 starts to increase as shown in FIG. As shown in FIG. 4 (b), the remaining VFA concentration also started to increase, and as shown in FIG. 4 (c), the methane gas generation rate also decreased. When the TS concentration became 10%, methane fermentation became impossible. On the other hand, in the case of Example 1 in which nutrients are added, as shown in FIG. 4, even when the TS concentration is increased, the methane fermentation treatment efficiency hardly decreases, and it can be seen that the methane fermentation treatment can be performed with high efficiency.

Further, in the same manner as in Example 1 shown in FIG. 4, the TS concentration was varied so that the volume load was 7.5 g / liter / day (2.4 g / liter / day in terms of TOC load). , About 55 which is a high temperature area in methane fermentation treatment
Methane fermentation treatment was performed at ℃. The result is shown in FIG.

In the second embodiment shown in FIG. 5, as in the first embodiment shown in FIG.
%, The activity of the anaerobic microorganisms can be prevented from decreasing, and the methane treatment can be performed with high efficiency.

Next, a mixture of the synthetic waste of Example 2 shown in FIG. 5 and the dewatered sludge obtained by the treatment of the human wastewater at a ratio of 1 to the synthetic waste 9 was similarly used. Methane fermentation was performed in a high temperature range. FIG. 6 shows the result.

In the third embodiment shown in FIG. 6, similarly to the first embodiment shown in FIG. 4 and the second embodiment shown in FIG. 5, when nutrients are added, anaerobic microorganisms having a TS concentration of 5% or more can be obtained. It can be seen that a decrease in activity can be prevented, and methane treatment can be performed with high efficiency.

Next, the efficiency of the methane fermentation treatment according to the type of nutrient added was compared. As an experimental method, in Comparative Example 1 and Comparative Example 2, the sludge obtained when the methane fermentation was stopped at a TS concentration of 10% was taken out, transferred to a vial bottle, and various nutrients were added. Of methane fermentation was observed. The processing temperature is about 36 ° C. which is a medium temperature range and about 5 ° C. which is a high temperature range.
The test was performed at 5 ° C. The nutrients were ferrous chloride 100 mg / l (iron concentration 44 mg / l), nickel chloride 10 mg / l (nickel concentration 4.5 mg / l), and cobalt chloride 10 mg / l.
Liter (4.5 mg / liter as cobalt concentration). The results are shown in FIGS.

From the results shown in FIG. 7, in the comparative example in which no nutrients were added, the methane fermentation treatment hardly proceeded from about 20 days of operation, but the methane fermentation treatment did not stop even with cobalt alone. ,In particular,
As shown in FIG. 8, it can be seen that the efficiency of the methane fermentation treatment is higher under the condition where the treatment temperature is high than when only iron or nickel alone is not added. In addition, it can be seen that the combination of iron, nickel and cobalt further increases the methane fermentation treatment efficiency.

As described above, from various experiments, even when the processing load such as COD, BOD, and TOC load is low, the TS
When the concentration was 5% or more, it was recognized that the accumulation of organic acids increased, and that the methane fermentation treatment decreased due to rancidity.
This is not because the activity of methanogens corresponding to the load is reduced simply by increasing the treatment load, and the methane fermentation treatment is not reduced. This is considered to be because the inactivating effect of nutrients necessary for the methanogen increases and the ingestion becomes impossible, and the activity of the methanogen decreases. Therefore, when the TS concentration is 5% or more, iron, cobalt,
It was found that by adding an appropriate amount of nickel, a nutrient balance suitable for methane fermentation with a high input solid concentration was secured and stable methane fermentation was steadily performed. In particular, when the treatment temperature was high, the treatment efficiency was significantly improved by the addition of nutrients.

[0057]

According to the waste treatment method of the present invention, when the crushed material obtained by crushing the waste containing organic waste is subjected to methane fermentation treatment with an anaerobic organism, the total amount of the crushed material is reduced. When the evaporation residue is 5% or more, at least one of an iron compound, a cobalt compound, and a nickel compound is added. The increased amount of the inactive effect of the nutrients of the anaerobic microorganisms such as iron, cobalt, and nickel can be replenished, thereby ensuring nutrient balance and improving the treatment efficiency of methane fermentation.

According to the waste disposal method of the second aspect,
When methane fermentation treatment of organic wastewater with anaerobic organisms,
The mixture containing solid organic waste is crushed, stirred and mixed to prepare a mixture, and the total evaporation residue of this mixture is 5%.
In the case described above, to add at least one of an iron compound, a cobalt compound and a nickel compound,
In order to increase the amount of methane gas produced and increase its effective utilization, the conditions for the concentration of the total evaporation residue are set to be high, so that the iron, cobalt and nickel contents of nutrients of anaerobic microorganisms contained in the crushed material are reduced. The increased amount of the activating effect is replenished, the nutrient balance can be secured, and the processing efficiency of methane fermentation can be improved.

According to the waste disposal method of the third aspect,
In addition to the effects of the waste disposal method according to claim 1 or 2,
The solid matter is mixed with the solid matter of the human wastewater when the waste is subjected to methane fermentation. Efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a waste disposal method according to the present invention.

FIG. 2 is a block diagram showing a configuration of another embodiment of the waste disposal method of the present invention.

FIG. 3 is a timing chart showing the results of an experiment in which methane fermentation was performed using synthetic waste in the processing step shown in FIG.

FIG. 4 is a timing chart showing the results of an experiment in which methane fermentation treatment was performed under conditions of a medium temperature range with the input TS concentration varied and the CODCr load kept constant using synthetic waste in the treatment process shown in FIG.

FIG. 5 is a timing chart showing the results of an experiment in which methane fermentation treatment was performed under conditions of a high temperature region with the input TS concentration varied and the CODCr load kept constant using synthetic waste in the treatment process shown in FIG.

FIG. 6 is a timing chart showing the results of an experiment in which methane fermentation was performed under conditions of a high temperature range with the input TS concentration varied and the CODCr load kept constant using synthetic waste in the processing step shown in FIG.

FIG. 7 is a graph showing the methane fermentation treatment status according to the type of nutrients added in the treatment step shown in FIG.

8 is a graph showing the methane fermentation treatment status at different temperatures according to the type of nutrients added in the treatment step shown in FIG.

[Explanation of symbols]

 1 Pretreatment means 3 Nutrient addition means 4 Methane fermentation digester as methane fermentation means

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshio Okuno 2-9-1, Noribori, Nishi-ku, Osaka-shi, Osaka Inside Ataka Industry Co., Ltd. (56) References JP-A-6-246288 (JP, A) JP-A-Hei 3-165895 (JP, A) JP-A-4-300968 (JP, A) JP-A-3-12296 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B09B 3/00 C02F 11 / 04,3 / 28

Claims (3)

(57) [Claims] 1. A waste treatment method for methane fermenting a crushed waste containing solid organic waste that can be decomposed by anaerobic organisms, comprising: 5% total evaporation residue
In the above case, a waste disposal method characterized by adding at least one of an iron compound, a cobalt compound and a nickel compound. 2. A waste treatment method for subjecting organic wastewater decomposable by anaerobic microorganisms to methane fermentation treatment, wherein the organic wastewater contains solid organic waste decomposable by anaerobic organisms. A mixture is prepared by crushing, stirring and mixing the waste, and when the mixture is subjected to methane fermentation treatment and the total evaporation residue of the mixture is 5% or more, at least one of an iron compound, a cobalt compound, and a nickel compound. A waste disposal method characterized by adding a compound. 3. The waste treatment method according to claim 1, wherein methane fermentation treatment is carried out together with the solid matter of the human wastewater from which the waste is solid-liquid separated.